The present invention relates to dental prosthetic devices, and more particularly, to crowns.
The prior art methods for providing crowns on teeth are very labor intensive and expensive. Such procedures require the making of molds from the patient's mouth and casting a precisely fitting crown from such molds. This is called the "indirect technique" because the work is accomplished at a laboratory distant from the patient.
Another procedure for providing crowns is to use prefabricated crowns, often made of a non-corrosive material such as stainless steel. These prefabricated crowns often cannot be used for restorations because of the great difficulty of achieving an adequate fit and adequate relationship to the adjacent and opposing teeth. Additionally, the prefabricated crowns are often thin walled and unable to withstand the forces exerted during biting or chewing without wear. Additionally, these prefabricated crowns have almost no adjustment capability and cannot be shaped by a dental bit due to the thin wall.
In addition to the cost and complexity of the indirect technique and the difficult problem of fitting a prefabricated crown, the prefabricated crowns have the problem that if the crown is ever damaged or falls off, the underlying tooth is left exposed. The pain caused by this exposure can result in a disabling emergency situation.
Additionally, teeth prepared for indirect fabrication crowns require extensive removal of external tooth structure usually extending beneath the gingival crest. This results in tooth sensitivity and gingival injury with a danger of development of periodontal disease.
Accordingly, it is desirable to provide dental crowns and methods therefor which are inexpensive and can be fitted right in the patient's mouth without subsequent molds being required. It is also desirable to provide dental crowns and methods therefor which can be prefabricated and do not require precision fitted prefabricated devices. It is also desirable to provide a dental crown which when damaged or lost, the tooth will still be protected. It is further desirable to provide a prefabricated crown which is adjustable at the time of installation.